You can pull some pretty mean power without Armageddon, two turns MIGHT be enough. It's stacked in MC3s favor with the arbitrary 999hp thing though.
Shhhhh... everybody, don't tell, FScell, but I'm implying that at each of their respective maximum levels of power, any attack other than an almighty one would more than likely be nulled or absorbed, and while the P3 MC could easily tank a mind charged Black Viper with all his final equipment, the P4 MC can't do a damn thing about Armageddon that drains more HP than he's even allowed to have by default. Basically, if my level 99 P4 protag fought my level 99 P3 protag, he'd die. Quickly. Mostly because he'd be too busy trying to bone her. And what's this 'balance' thing? That's what little kids say when they want their favorite hero to win. "UUUMMMMM, YOU CAN'T USE XXX, XXX, XXX, XXX, XXX OR NULL ANY OF MY ATTACKS BECAUSE I'D DIE INA SECOND IF YOU DID AND I WANT TO WIN"~otherwise known as the cryptinite-less Batman versus Superman clause. (not that I'm implying that FScell favors the P4 protagonist) Shhhhh.... don't tell him/her/whatever.